A retrovirus designated human immunodeficiency virus (HIV), particularly the strains known as HIV type-1 (HIV-1) virus and type-2 (HIV-2) virus, is the etiological agent of the complex disease that includes progressive destruction of the immune system (acquired immune deficiency syndrome; AIDS) and degeneration of the central and peripheral nervous system. A common feature of retrovirus replication is the insertion by virally-encoded integrase of proviral DNA into the host cell genome, a required step in HIV replication in human T-lymphoid and monocytoid cells. Integration is believed to be mediated by integrase in three steps: assembly of a stable nucleoprotein complex with viral DNA sequences; cleavage of two nucleotides from the 3′ termini of the linear proviral DNA and covalent joining of the recessed 3′ OH termini of the proviral DNA at a staggered cut made at the host target site. The fourth step in the process, repair synthesis of the resultant gap, may be accomplished by cellular enzymes.
Nucleotide sequencing of HIV shows the presence of a pol gene in one open reading frame [Ratner, L. et al., Nature, 313, 277(1985)]. Amino acid sequence homology provides evidence that the pol sequence encodes reverse transcriptase, integrase and an HIV protease [Tohours, H. et al., EMBO J. 4, 1267 (1985); Power, M. D. et al., Science, 231, 1567 (1986); Pearl, L. H. et al., Nature, 329, 351 (1987)]. All three enzymes have been shown to be essential for the replication of HIV.
It is known that some antiviral compounds which act as inhibitors of HIV replication are effective agents in the treatment of AIDS and similar diseases, including reverse transcriptase inhibitors such as azidothymidine (AZT) and efavirenz and protease inhibitors such as indinavir and nelfinavir. The compounds of this invention are inhibitors of HIV integrase and inhibitors of HIV replication.
The following references may be of interest as background:    International Publication Nos. WO 11/045330 and WO 11/121105 disclose macrocyclic compounds having HIV integrase inhibitory activity.    Kinzel et al., Tet. Letters 2007, 48(37): pp. 6552-6555 discloses the synthesis of tetrahydropyridopyrimidones as a scaffold for HIV-1 integrase inhibitors.    Ferrara et al., Tet. Letters 2007, 48(37), pp. 8379-8382 discloses the synthesis of a hexahydropyrimido[1,2-a]azepine-2-carboxamide derivative useful as an HIV integrase inhibitor.    Muraglia et al., J. Med. Chem. 2008, 51: 861-874 discloses the design and synthesis of bicyclic pyrimidinones as potent and orally bioavailable HIV-1 integrase inhibitors.    US2004/229909 discloses certain compounds having integrase inhibitory activity.    U.S. Pat. No. 7,232,819 and US 2007/0083045 disclose certain 5,6-dihydroxypyrimidine-4-carboxamides as HIV integrase inhibitors.    U.S. Pat. No. 7,169,780, U.S. Pat. No. 7,217,713, and US 2007/0123524 disclose certain N-substituted 5-hydroxy-6-oxo-1,6-dihydropyrimidine-4-carboxamides as HIV integrase inhibitors.    U.S. Pat. No. 7,279,487 discloses certain hydroxynaphthyridinone carboxamides that may be useful as HIV integrase inhibitors.    U.S. Pat. No. 7,135,467 and U.S. Pat. No. 7,037,908 disclose certain pyrimidine carboxamides that may be useful as HIV integrase inhibitors.    U.S. Pat. No. 7,211,572 discloses certain nitrogenous condensed ring compounds that are HIV integrase inhibitors.    U.S. Pat. No. 7,414,045 discloses certain tetrahydro-4H-pyrido[1,2-a]pyrimidine carboxamides, hexahydropyrimido[1,2-a]azepine carboxamides, and related compounds that may be useful as HIV integrase inhibitors.    U.S. Pat. No. 8,129,385 discloses certain hexahydro-2H-pyrido[1′,2′:4,5]pyrazino[2,1-b][1,3]oxazine-9-carboxamides, and related compounds that may be useful as HIV integrase inhibitors.    WO 2006/103399 discloses certain tetrahydro-4H-pyrimidooxazepine carboaxmides, tetrahydropyrazinopyrimidine carboxamides, hexahydropyrimidodiazepine carboxamides, and related compounds that may be useful as HIV integrase inhibitors.    US 2007/0142635 discloses processes for preparing hexahydropyrimido[1,2-a]azepine-2-carboxylates and related compounds.    US 2007/0149556 discloses certain hydroxypyrimidinone derivatives having HIV integrase inhibitory activity.    Various pyrimidinone compounds useful as HIV integrase inhibitors are also disclosed in U.S. Pat. No. 7,115,601, U.S. Pat. No. 7,157,447, U.S. Pat. No. 7,173,022, U.S. Pat. No. 7,176,196, U.S. Pat. No. 7,192,948, U.S. Pat. No. 7,273,859, and U.S. Pat. No. 7,419,969.    US 2007/0111984 discloses a series of bicyclic pyrimidinone compounds useful as HIV integrase inhibitors.    US 2006/0276466, US 2007/0049606, US 2007/0111985, US 2007/0112190, US 2007/0281917, US 2008/0004265 each disclose a series of bicyclic pyrimidinone compounds useful as HIV integrase inhibitors.    U.S. Pat. No. 7,462,608 and U.S. Pat. No. 7,649,015 each disclose phosphate and phosphonate substituted heterocycles useful as HIV nNRTI inhibitors and HIV protease inhibitors, respectively.